Alignment of a firearm for firing presents problems peculiar to firearms such as rifles and shotguns, particularly when shooting at moving targets. Shooting at fowl, or skeet shooting requires rapid aim and immediate response by the target shooter. The target is moving and the time for getting off the shot is limited. It is understood in shooting, such as in trapshooting or fowl shooting, that because of the often rising motion of the target, and the tracking motion imparted to the weapon by the shooter, the gun should be aligned to shoot above the point of aim. The amount of this "rise" or elevation depends upon the distance to the target, and indeed, also upon the individual preference of the shooter. The purpose is to secure an alignment that will provide a shot pattern centered on the target which could also be a stationary target at the selected distance.
In U.S. Pat. No. 2,795,048 to Seymour, et al, June 11, 1957, for "Detachable Rear Sight For Shotguns", the patentee proposes a detachable sight for mounting on a shotgun to provide for aiming in the manner of a rifle for use when firing slug shot. U.S. Pat. No. 3,945,142 to Keppeler, March 23, 1976 for "Mount For A Sight On Firearms" describes a mount for a rifle, or the like, by applying a ring to the finished rifle or gun.
U.S. Pat. No. 3,975,851 to Benford, Aug. 24, 1976 for "Slug-ster Sight For A Shotgun", provides a detachable mounting on the rear barrel of a shotgun for a sight. The sight has a ramp for vertical adjustment of the sight, thereby providing adjustment for elevation. The sight is intended for use with a shotgun when employed with shot and a slug. U.S. Pat. No. 4,008,536 to Adams, Feb. 22, 1977 for "Detachable Gun Sight Mounts" describes a gun sight mount for front or rear sights which may be attached to a shotgun with a ventilated rib sight mount. A modification permits mounting when a ventilated sight rib is absent. In either case, the patentee proposes to mount a pair of such mountings on a gun, and on these readily attachable and detachable gun sight mountings a conventional rifle sight may be mounted.
U.S. Pat. No. 4,010,564 to Pettit, Mar. 8, 1977, for "Shotgun With Adjustable Ventilated Sight Rib" describes a ventilated sight rib mounting for a shotgun having a mechanism for adjusting the elevation of the forward part of the sight. The sight rib is pivoted at its rearward end on a horizontal transverse axis by adjusting links at the forward end of the rib. The rib may move slidably to permit the adjustment. U.S. Pat. No. 4,117,617 to Linde, et al, Oct. 3, 1978 for "Adjustable Sighting Rib" suggests a shotgun having a sighting rib. The slope of the rib is adjusted by raising (or lowering) the front of the rib more than the rear of the rib in such a manner that the center of rotation is approximately at the point where a shooter places his eye when aiming. By this means, the patentee suggests the shooter may place his cheek at the same place on the stock at each shot, rather than adjust for the different positions of the rib. U.S. Pat. No. 4,143,465 to White, Mar. 13, 1979 for "Sighting Device" describes an attachment for a shotgun rib to allow ready adjustment of the sights for different elevation of the shot pattern. The purpose is to provide a shotgun sighting that is readily adjustable.